Grain size distribution, bulk density, and percent carbon are reported for sediment samples from two flooded agricultural tracts, Little Holland Tract and Liberty Island, in the Sacramento-San Joaquin Delta, California. Samples were repeatedly collected at 8 sites using a Ponar grab or push core samplers during 19 visits to the study area from 2015 to 2019. The long-term time series data collection stations (sites LWA, HVB, HWC, and LVB) were sampled on almost every field survey, and the remaining sites were sampled 6 or times or fewer, some only once. All samples were analyzed for grain size distribution, and some were analyzed for bulk density and/or percent carbon. These data provide insight into how particle size distributions varied spatially and temporally.